Bacterial persistence to antibiotics activated by tRNA mutations.

Area of Science:

• Microbiology
• Genetics
• Molecular Biology

Background:

• Bacterial persistence contributes to difficult-to-treat chronic and relapsing infections.
• The precise molecular mechanisms driving bacterial persistence remain largely unknown.

Purpose of the Study:

• To investigate novel mechanisms underlying bacterial persistence.
• To identify genetic mutations associated with antibiotic tolerance in *Burkholderia thailandensis*.

Main Methods:

• Isolation and whole-genome sequencing of antibiotic-tolerant *Burkholderia thailandensis* mutants.
• Characterization of mutant phenotypes using killing curves, growth curves, and persistence-fraction plots.
• Analysis of uncharged tRNA and the role of the stringent response (RelA/SpoT) in persistence.

Main Results:

• Discovered a novel persistence mechanism mediated by mutations in the anticodon loop of tRNAAsp (positions 32 or 38).
• These tRNA mutations induce a RelA-dependent stringent response, leading to heightened antibiotic tolerance.
• Demonstrated phenotypic reversion to wild-type physiology by loss of the mutant tRNA allele.

Conclusions:

• tRNA mutations at specific anticodon loop positions represent a novel mechanism for bacterial persistence.
• The stringent response plays a critical role in this antibiotic tolerance.
• The tRNA gene cluster facilitates adaptability, enabling bacteria to regulate persistence for survival.